JPS5996065A - Synthesized controller with suspension and steering - Google Patents

Abstract

PURPOSE:To obtain the steering characteristic corresponding to a variety of demands by varying the steering characteristic so that the variation of the steering characteristic generated in accordance with the variation of the suspension characteristic is promoted or offset. CONSTITUTION:When the suspension characteristic is selected by a manual switch 32, a solenoid 58 is excited by turning-off the switch 32, and the steering turning ratio is increased by a reduction gear, and then the solenoid 58 is deenergized by turning-off the switch 32, and the speed is reduced by the reduction gear, and the turning ratio is reduced. Therefore, when the switch 32 is Off, the increase of stability and the reduction of the response performance which are caused by the strong under-steer in the suspension characteristic are offset by increasing the turning ratio, and when the switch 32 is on, the reduction of stability and the increase of the response performance caused by the weak under-steer are offset. When an inverter 35 is removed, the excitation and deenergizing of the solenoid 58 is reversed, and the steering characteristic in which the variation of the suspension characteristic is promoted can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a suspension in which at least one of damper damping characteristics and spring characteristics (hereinafter referred to as suspension characteristics) is variable, and steering characteristics (for example, steering angle characteristics relative to front wheel turning angle). The present invention relates to a comprehensive suspension and steering control device that controls steering characteristics in accordance with control of the suspension characteristics in a vehicle equipped with a steering device that has variable suspension characteristics.

BACKGROUND ART In automobile suspensions, systems have been proposed in which the damping force of a damper is controlled depending on the situation.

For example, as shown in Japanese Utility Model Application No. 55-109008, a vehicle is known in which the damping force is changed depending on the vehicle speed to always obtain favorable handling characteristics. Suspensions consist of a combination of dampers and springs, and it is also possible to obtain similar handling characteristics by changing the spring characteristics entirely. These systems strengthen the understeer characteristics at high speeds to increase straight-line stability, and weaken the understeer characteristics at low speeds to increase turning performance, so that favorable handling characteristics can always be obtained in response to changes in vehicle speed. Changing the understeer characteristics will change the handling characteristics (steering feel). That is,
Increasing the understeer characteristic increases the steering force, making the steering heavier and decreasing the response during steering. Reducing the understeer characteristic decreases the steering force, making the steering lighter and reducing the response during steering. The tendency to become more sensitive is strengthened.

Moreover, the steering performance can also be changed by changing the steering characteristics. For example, in power steering, by changing the steering assist force, and in manual steering, by changing the steering assist force.
Ratio between wheel steering angle θ8 and front wheel turning angle θ, 0F/θ8
(hereinafter referred to as steering rotation ratio), the steering characteristics, i.e., when the assist force is reduced with power steering, or when the steering rotation ratio is reduced with manual steering,
The response during steering becomes dull and the steering sensation becomes anchor-like.On the other hand, when the steering force is increased with power steering or when the above ratio is completely increased with manual steering, the response during steering becomes sharp and the steering sensation becomes anchor-like. becomes sharp.

Examples of changing the steering characteristics include changing the entire steering operation depending on the vehicle speed, as shown in Japanese Patent Application Laid-Open No. 55-55059, making the steering heavier at high speeds to increase straight-line stability, and changing the steering at low speeds. It is known that the weight is reduced to improve turning performance.

As mentioned above, in the past, by separately controlling the suspension characteristics or steering characteristics, it was possible to increase straight-line stability during high-speed driving, where lane changes or relatively gentle curves were mostly involved. Turning performance is increased during low-speed driving where there is a lot of sharp cornering.

However, the senses and preferences of drivers vary greatly, and it is extremely difficult to create a car with performance that satisfies all drivers. For example, when it comes to handling characteristics, some people prefer a car with a sporty feel that is responsive to steering operations, while others prefer a quiet car that emphasizes stability. People with less power may prefer lighter steering.

For this reason, if you emphasize the performance of one, you will inevitably sacrifice the other.

In view of the above-mentioned circumstances, an object of the present invention is to provide a comprehensive suspension and steering control device that allows selection of various steering characteristics by changing steering characteristics in accordance with changes in suspension characteristics.

The integrated control device for suspension and steering according to the present invention controls at least one of the damping force of the damper of the suspension unit or the spring constant of an air spring, etc. to adjust the damping ratio or spring constant ratio of the front wheels to the rear wheels. In addition to variably controlling the rotation ratio of the steered wheels to the steering wheel of the steering device, the suspension characteristics and steering characteristics can be controlled in relation to each other. It is characterized by the fact that

According to the present invention, since the steering characteristics can be controlled in accordance with the control of the suspension characteristics, changes in the steering characteristics caused by changing the suspension characteristics and increasing the understeer characteristics can be controlled by changing the steering characteristics. By promoting or canceling out changes in the steering characteristics caused by the changes, it is possible to obtain steering characteristics that meet various demands. That is, Suspense 7
The change in understeer characteristics due to the steering wheel causes a difference between sluggishness and sharpness in the steering sensation, but this can be enhanced by changing the steering characteristics, making it even more sluggish and sharp, or canceling each other out to eliminate the difference. This allows a variety of maneuvering characteristics to be obtained.

Specifically, if the suspension characteristics can be switched to strong or weak understeer by manual switch operation, etc., by changing the steering characteristics along with this change, the change in understeer characteristics can be clearly felt as a human sensation. You can obtain two types of handling characteristics: either it makes you feel it, or it doesn't make you feel it. For example, when the suspension characteristic has strong understeer, the rotation ratio (θF/θ
S), and conversely, when the understeer is weak, the rotation ratio (θF/θ8) is set to be large. When the strong understeer with the suspension suspension/yon characteristic is selected by a switch etc., the stability due to the strong understeer can be improved. This tendency to increase in steering speed is facilitated by reducing the turning ratio (θF/θS), resulting in excellent straight-line stability and reduced responsiveness.On the other hand, when weak understeer is selected, this The tendency for responsiveness to improve due to weak understeer is the turning ratio (θF/
By increasing θ8), it is possible to obtain steering characteristics with excellent responsiveness and suppressed straight-line stability. Furthermore, the rotation ratio (θF/θ8) for strong understeer is increased, and the rotation ratio (θF/θ8) for weak understeer is increased.
When set to be small, the change in responsiveness or stability due to changes in understeer is canceled out by the steering characteristics (the rotation ratio (0F/θs)), which is exactly the opposite of the case described above. Stability or responsiveness is achieved depending on the characteristics, but the steering characteristics are such that you do not feel any change in understeer characteristics.Of the above two types of steering characteristics, one of the characteristics is selected at the time of design. It is also possible to set the vehicle as a vehicle, and it is also possible to make it switchable by means such as a switch that can be freely selected by the driver.

On the other hand, there is a system that automatically controls suspension characteristics in accordance with the driving conditions of the vehicle (eg, vehicle speed, load, steering angle, etc.). In the case where the control characteristics are selected using the manual switch mentioned above, there is a problem that if the characteristics are excellent in straight-line stability, the characteristics are inferior when turning.However, if the automatic control method is used, this problem can be overcome. It can be resolved.

In this case as well, two-way steering characteristics can be obtained. For example, the suspension characteristics change at high speed depending on the vehicle speed.
For example, if the control is such that the steering is strong and the understeer is weak at low speeds, the rotation ratio (
There are two ways to do this: to reduce 0F/θ8) and increase the rotation ratio at low speeds, and to do the exact opposite. When the rotation ratio is made smaller at high speeds and larger at low speeds, the tendency to increase stability at high speeds and the tendency to increase responsiveness at low speeds due to changes in understeer characteristics are promoted by changes in steering characteristics due to changes in rotation ratio, resulting in improved stability at high speeds and at low speeds. Turning ability will be emphasized, resulting in so-called sporty handling characteristics. Conversely, if the rotation ratio is increased at high speeds and decreased at low speeds, stability at high speeds tends to increase due to changes in understeer characteristics, and responsiveness at low speeds increases. This tendency is offset by changes in steering characteristics, and the car's state is designed to achieve high-speed stability and low-speed turning performance in accordance with the understeer characteristics, but the steering sensation (is not affected by the understeer characteristics). .

The above characteristics can be summarized as shown in the following table.

Embodiments of the present invention will be explained in detail below with reference to the drawings.

FIG. 1 shows an example of an automobile equipped with a comprehensive control device according to an embodiment of the present invention, in which a solenoid that changes damper damping force based on input from a vehicle speed sensor 31 and/or a manual switch 32 is shown. 21
b, 22b or solenoid 2 that changes the spring characteristics
An output for operating 1a+22a or both is outputted from the entire controller 3o to change the suspension characteristics, and at the same time, an output for changing the gear ratio of the steering speed reduction device 50 is sent from the controller 3o to change the steering characteristics.

FIG. 2 shows a main system diagram of an embodiment according to the present invention, in which the upper steering shaft 2a rotated by the steering wheel l is connected to a steering speed reducer 50. The lower steering shaft 2b and the joint 3.4'i are connected to the pinion 5, so that the rotation of the steering wheel l is slowed down by the steering speed reducer 50 and then rotates the pinion 5. This pinion 5 is meshed with a rack 6, and shafts 7a and 7bi are attached to both ends of this rack 6.
a knuckle arm 8 a rotatably supported at the center;
SbK engaged tie rods 9a and gb are connected. The rack 6 can be moved left and right in the figure by rotating the vinyl 1f 50 times, and the tie rod 9a.

Move the knuckle arms 8a, 8b'tD through 9bi,
Gives a steering angle to the steering wheels (generally front wheels) 10a and 10b.

The output from the steering reducer 507d controller 30 transmits the rotation of the upper steering shaft 2a to the lower steering shaft 2b in a decelerated or direct manner to change the steering characteristics.Details are shown in the figure. Shown in the enlarged view. The lower end of the upper steering shirt 2a has a gear 51a (number of teeth: 22) and an external spline 51b, and the gear 51a is a gear 52 on a first gear body 52 that rotates freely on a fixed shaft 59.
a (number of teeth: Z2), and another gear 52b (number of teeth: Z3) on the gear body 52 rotates on the lower steering shaft 2b and has an outer spline 53b and a gear 53a'i. Gear 53a of 2-gear body 53 (number of teeth:
It meshes with Z4). Therefore, from the gear 51a at the end of the upper steering shaft 2a to the gear 53a of the second gear body 53.
When the rotation is transmitted to, the reduction ratio: (Z1/Z2) x
A deceleration of (Z3/Z4) is performed. The upper end of the lower steering shaft 2b also has an external spline whose axis is aligned with the upper steering shaft 2a. Tooth spline 54b and second gear body spline 53b
are adjacent to each other in this order, have the same specifications, and are on the same axis. Therefore, the sleeve 55, which has an internal spline that meshes with this spline, meshes with any of the three splines mentioned above, and furthermore, the sleeve 55 that has the internal spline that meshes with this spline meshes with any of the three splines mentioned above. It can be slid in the middle and up and down directions.

On the other hand, a groove 55a provided on the outer periphery of this sleeve 55 allows a gift 56 to be slid up and down in the reducer case 60 as shown in the figure.
The protrusion (fork) 56a is fitted, and the sleeve 55 also moves up and down in accordance with the up and down of the gift 956. Furthermore, this shaft 56 is urged downward in the figure by a spring 57, and when the solenoid 58 is excited by the output 30g from the controller 30, the shaft 56 is pulled upward by overcoming the urging force of this spring 57. When the solenoid 58 is demagnetized, it is lowered downward.

Therefore, the sleeve 55 moves up and down by the energization and demagnetization of the solenoid 58, and the sleeve 55 moves upward. In other words, when the solenoid 58 is energized in this figure, the internal spline of the sleeve 55 causes the upper steering wheel and the external spline 51b of the sleeve 2a. and the external spline 53b of the lower steering shaft 2b at the same time, thereby moving the upper and lower steering shafts iMt-. 7L//A spring 570 is used to demagnetize the id 58, and the shaft 56 and the sleeve 55 are located at the bottom in the figure.・External spline 54 of shaft 2b
The rotation of the steering wheel is controlled by the gear train shown in the diagram at the reduction ratio: (Z+ / Z2
) × (Z3/Z4)
Rotate. As described above, the output 3ogK of the controller 3o is deenergized and excited with the solenoid 58, and the steering characteristics can be changed by completely changing the steering rotation ratio.

On the other hand, the controller 3o receives input from the power supply as well as
Input 30a from the manual switch 32 when switching to manual operation is possible, input 30h from the steering angle sensor 33 in this embodiment, input 30f from the vehicle speed sensor 3 (some of the above inputs are selected). ) are input and the suspension characteristics change based on these input signals 30b.

30cy30d and 30ei are output, and the above-mentioned signal 30g' follows this output and changes the steering characteristics completely.
i will come out.

Specifically, the steering characteristics are as described above, and regarding the suspension characteristics, for example, the air springs 21, 2
To change the spring characteristics of 2, output 30b from controller 3o.

30c energizes or demagnetizes the solenoids 21a and 22a, and turns on the communication with the actuators 21A and 22A.
To change the damping characteristics of the damper, output 30d, 30eK from the controller 30.
, j:9 Solenoids 21b and 22b are energized or demagnetized to change the orifice size that determines the damper characteristics.

As described above, it is possible for the controller to control steering characteristics that follow changes in suspension characteristics, either manually or automatically by selection of a switch, depending on the steering angle (or driving conditions such as load and vehicle speed).

FIG. 3 shows a control circuit according to a first embodiment of the present invention, and shows a case where suspension characteristics can be freely selected by a manual switch. manual·
When the switch 32 is OFF, this signal 30a is input to the controller 30, and from this controller 011i"
F signal is output to front wheel suspension/con 23 3 Q b ,
30 d, demagnetize the solenoid 21a that changes the spring characteristics of the An wheel suspension pennmin 23 or the solenoid 21b that completely changes the damping characteristics, or both, and output 30 c which becomes a pON signal by the power cylinder 1 inverter 34. , 30 energize the solenoid 22a that changes the spring characteristics of the wheel f suspension 24, the solenoid 22b that changes the damping characteristics, or both. In this case, the solenoid 21 that changes the spring characteristics
a, 22a is a solenoid 21b whose spring constant is set to be small during excitation (ON) and large when demagnetized (C)FF), changing the damping characteristic.

22b reduces the damping force when excited (ON).
It is set so that it becomes larger when p). When the manual switch 32 is ON, the spring characteristic change solenoid 21a of the front wheel suspension 23, the damping characteristic change solenoid 21b, or both are energized, which is the opposite of the above case, and the spring characteristic change of the rear wheel suspension/controller 24 is energized. For Renoi M22a or damping characteristic change solenoid 22
b or both are demagnetized. Here, the spring constant of the front wheel suspension is 2KF, the damping coefficient is CF, the spring constant of the rear wheel suspension is KR1, and the damping coefficient is CR, and the value for 0N-OFF of the manual switch 32 is O.
When expressed with a suffix of N or OFF, it becomes as follows.

l) Spring constant ratio (KF/KR) OFF> (KF/KR
). N2) Damping coefficient ratio (CF/CR) OFF〉(CF/
By turning CR) ON, the understeer characteristic becomes strong when the manual switch is OFF, and the understeer characteristic becomes weak when the manual switch is OFF. The above points can be summarized as shown in Table 2 below.

γ ζ Hi? In response to the input jOa of the manual switch 32 that changes the suspension characteristics as described above, an output 30b is sent to the suspension side.

In addition to 30c, 3od, and 30e, the output 30g to the solenoid 58 that changes the ON/C steering characteristics is also reversed from ON to OFF by the second inverter 35 and output. In the example shown in this figure, when the manual switch is OFF, the solenoid 58 is energized, and the upper steering shaft 2a and lower steering shaft 2b are directly connected by the reducer 5o explained in FIG. When the solenoid 58 is demagnetized, the rotation of the upper steering shaft 2a is reduced by the reducer 50 and transmitted to the lower steering shaft 2b, and the steering rotation ratio becomes smaller. Therefore, when the manual switch 32 is OFF, the steering rotation ratio is large due to strong understeer due to the suspension characteristics, and the tendency to increase stability and decrease responsiveness due to strong understeer is offset by increasing the steering rotation ratio. When ON, the steering rotation ratio is small due to weak understeer due to suspension characteristics, and by reducing the steering rotation ratio to offset the tendency for stability to decrease and responsiveness to increase due to weak understeer, the driver does not notice changes in suspension characteristics. Maneuvering characteristics can be obtained.

FIG. 4 shows a control circuit of a second embodiment according to the present invention, and the only difference from the embodiment shown in FIG. 3 is that there is no second inverter 35 placed in front of the output 30g. Therefore, identical parts are given the same numbers and explanations are omitted.
I will. In the embodiment shown in this figure, the change in suspension characteristics by the manual switch 32 is exactly the same as in the example shown in Fig. 3, but the solenoid 5 that changes the steering rotation ratio
8 is reversed from the example shown in FIG. Therefore, when the manual switch 32 is OFF, the steering rotation ratio is small due to strong understeer due to the suspension characteristics, and the tendency to increase stability and decrease responsiveness due to strong understeer is promoted by reducing the steering rotation ratio, and when the manual switch 32 is ON. When understeer is weak due to suspension characteristics, the steering rotation ratio is increased (by increasing the steering rotation ratio to promote the tendency for stability to decrease and responsiveness to increase due to weak understeer, changes in suspension characteristics can be made more noticeable to the driver. You can get clear handling characteristics.

The characteristics of the embodiments shown in FIGS. 3 and 4 can be summarized as shown in Table 3.

Table 3 FIG. 5 shows a control circuit according to a third embodiment of the present invention, and shows a case where the suspension characteristics are automatically controlled based on the steering angle. In this figure, parts common to those in FIG. 3 are given the same numbers, and explanations thereof will be omitted.

The input 3oh from the steering angle sensor 33 is sent to the comparator 36.
(enters the + side, and a constant input from the power supply is connected to comparator 3.
Enter the (→ side of 6), perform comparison processing here, and output 0N-O.
Outputs FF signal.

That is, when the steering angle is smaller than a certain value, the comparator output is OFF, and when the steering angle is larger than a certain value, the comparator output is ON. Using this ON-OFF signal, the suspension characteristics and steering characteristics are controlled as in the case of FIG. Comparator output is OFF
In other words, when the steering angle is small and the steering angle is small and the driving state is straight or almost straight, the steering rotation ratio increases due to strong understeer due to the suspension characteristics, and the strong understeer increases stability and decreases responsiveness. By increasing kJs to compensate, when the comparator output is ON, that is, when the steering angle is large and the steering angle is large, the steering rotation ratio is small due to weak understeer due to the suspension characteristics, and the tendency for stability to decrease and responsiveness to increase due to weak understeer can be reduced by steering rotation. By reducing and offsetting the dynamic ratio, the car's stability and responsiveness are achieved according to the strength of understeer caused by the suspension characteristics, but the so-called gentle handling characteristics do not make the driver feel changes in the suspension characteristics. is obtained.

FIG. 6 shows a control circuit of a fourth embodiment according to the present invention, and the only difference from the embodiment of FIG. 5 is that there is no second inverter 35 placed in front of the output 30g. Since they are the same, the same parts as in FIG. 5 are given the same numbers and their explanation will be omitted. In the embodiment shown in this figure, the change in suspension characteristics caused by the ON-OFF signal from the comparator 36 depending on the magnitude of the steering angle is exactly the same as in the example shown in FIG. The excitation is reversed from the example in FIG. Therefore, the comparator 36
When the output of the comparator 36 is OFF, the steering rotation ratio is small due to strong understeer due to the suspension characteristics, and the tendency to increase stability and decrease responsiveness due to strong understeer is promoted by reducing the steering rotation ratio, and the output of the comparator 36 becomes OFF.
When in N, the steering rotation ratio is large due to weak understeer due to the suspension characteristics, and the stability decreases due to weak understeer and the tendency for responsiveness to increase. It has excellent responsiveness and turning performance when turning (so-called sporty maneuvering characteristics can be obtained).

The characteristics of the embodiments shown in FIGS. 5 and 6 can be summarized as shown in Table 4.

Table 4 The control circuit diagram shown in FIG. 7 shows an example in which suspension characteristic control is performed by both the steering angle sensor f33 and the vehicle speed sensor 31, and the way the amplifier 44b in this figure is output is shown in FIGS. 5 and 6. It is replaced with the (a) side input to the comparator 36 and forms a controller 30A. That is, FIG. 7 is a circuit diagram showing a portion of the controller 3o.

In this embodiment, the understeer characteristic is weakened according to the magnitude of the centrifugal force (θ x V2), which is the sum of the centrifugal force and the low centrifugal force during steering. A control example is shown in which the output θ of the steering angle sensor 33 and the output S of the vehicle speed sensor 31, which are input to the controller 3o△, are input to the controller 3o△ using a converter that converts the output S of the vehicle speed sensor into a voltage while keeping the steering angle θ unchanged. The output V converted by 41 is multiplied by xH42, which is then input to the multiplier 43 to obtain θxV2.
The output θ×V2 is sent to the amplifier 44a and the amplifier 4.4.
Front and rear wheel actuators 21a, 2 via b
lb, 22a, and 22b to control the damping force and spring constant. In other words, the vehicle speed (
2) multiplied by the steering angle (θ). Depending on the magnitude of the combined value, the damping force front and rear wheel ratio C"/C or the spring R constant front and rear wheel ratio Kj/is determined by the magnitude of and 9 values (θ×v2
) is controlled so that it becomes smaller as it becomes larger. This results in
Suspension characteristic control can be performed on the steering angle multiplied by the influence of centrifugal force that is proportional to the square of the vehicle speed.

Furthermore, by simultaneously inputting the above suspension characteristic control signal to the steering control side of the example shown in FIGS. 5 and 6, steering characteristic control that follows changes in suspension characteristics as in the example shown in FIGS. 5 and 6. can be done.

FIG. 8 is a graph showing the relationship between centripetal acceleration and steering angle in the embodiment of the present invention, and shows the relationship as the suspension characteristics and steering characteristics change. The solid lines (a and C) show the case where the steering rotation ratio θF/θ8 is decreased, the broken lines (b and d) indicate the case where the steering rotation ratio /θ8 is increased, and the upper line a
and b show an example where the understeer characteristics due to the suspension characteristics are strengthened, and the lower lines C and d show an example where the understeer characteristics due to the suspension characteristics are weakened. The embodiments shown in FIGS. 3 and 5 have the characteristics, and the embodiments shown in FIGS. 4 and 6 have the handling characteristics shown by the lines a and d.

As explained in detail above, according to the present invention, changes in steering characteristics caused by changes in suspension characteristics can be promoted or offset by changing steering characteristics by changing the rotation ratio of the steering wheel. Therefore, it is possible to realize a vehicle having various handling characteristics, such as steering characteristics that make the change in steering characteristics due to the change in suspension characteristics more clearly felt by the driver, and steering characteristics that do not make the driver feel it much.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an automobile equipped with the integrated control device of the present invention, FIG. 2 is a main system diagram of an embodiment of the present invention, and FIGS. 3 and 4 are twelfth and second embodiments of the present invention. FIG. 5 and FIG. 6 are control circuit diagrams of the third and fourth embodiments of the present invention. FIG. 7 is a control circuit diagram based on steering angle and vehicle speed. FIG. 8 is a steering angle control circuit diagram. It is a graph showing the relationship between and centripetal acceleration. 1... Steering wheel 2.2a, 2b... Steering shaft 3.4.
...Joint 5...Binion 6...Rack 21a, 21b, 22a, 22b...Solenoid 21
A, 22A...Accumulator 30...Controller 31...Vehicle speed sensor 32...Manual switch 33...Rudder angle sensor 34...First inverter 35...Second inverter 36...Comparator 41...Converter 44, a...Buffer 44b...Amplifier 5
0... Steering reducer 51a, 52a, 52b, 53a-gear 51b, 53b
, 54b... External spline 55... Sleeve
57...Spring 58...Renoid ¥S2 Fig. 3 Fig. 4 Fig. 4

Claims (1)

[Claims] A suspension unit that suspends the vehicle body on each of the front, rear, left and right wheels, a steering device that steers the steerable wheels among the wheels, and a damping force of the suspension unit that controls at least one of the spring constants of the front wheels. A second control means for variably controlling the damping force ratio or spring constant ratio of the rear wheels; a second control means for variably controlling the rotation ratio of the steered wheels relative to the steering wheel of the steering device; and a second control means for controlling the suspension unit. A comprehensive suspension and steering control device comprising a controller that issues control signals to the first control means and second control means so as to fully control the steering device.